The present invention relates to an apparatus for sealing and severing a web of film. More specifically, the present invention relates to an apparatus for creating side seals in a web of film in a form, fill and seal packaging machine and for severing the web of film between the side seals.
Typically, form, fill and seal packaging machines are utilized to package a product in a flexible container. To this end, form, fill and seal packaging machines are used to seal pharmaceuticals, dairy products, wine, food stuffs, cosmetics, and other products in flexible containers. The form, fill and seal packaging machine provides an apparatus for packaging these products in an expedient manner.
In one type of form, fill and seal packaging machine a web of heat-sealable film is passed over a former or mandrel that forms the film into a tubular shape. To effect a tubular shape, the film is folded longitudinally and heat sealed along abutting longitudinal edges. The tubular shaped film is then passed around a tubular fill system that deposits the product to be packaged into the tubular shaped film. To create individual packages (hereinafter "bags") the web of film must be sealed across its width. The side seals are typically created by a sealer that creates the second seal for one bag while making the first seal for the next bag. After the side seals are created, the web of film may then be severed between the seals to create individual bags.
One method of creating the side seals in the web of film is to utilize a hot bar. The hot bar is secured to a set of jaws that are hydraulically actuated to grip the web of film. As the jaws grip the web of film the hot bar is urged against the web of PG,3 film melting a portion of the web of film onto itself. Typically, after the hot bar has melted the web of film a knife is actuated and severs the web of film between the seals to create a flexible bag.
In the embodiment of the form, fill and seal packaging machine set forth above, the time and pressure at which the hot bar is urged against the web of film is determined by the jaws. Because the hot bar is secured to and actuated with the jaws, the pressure at which the jaws are urged against the web of film is the pressure at which the hot bar is urged against the web of film. In a similar vein, the time during which the hot bar engages the film is determined by the time the jaws engage the film. Accordingly, it is not possible to independently vary the time and pressure the hot bar engages the web of film.
As set-forth above, it is common for the web of film to be severed between side seals by an actuated knife. Typically, this method of severing the web of film results in an excess amount of waste, i.e., excess film being located on the sides of the bag created.
Accordingly, there is a need for an improved apparatus for sealing and severing a web of film.